vb.net - vb.net - 如何使用参数将新任务声明为 SUB

Question

如您所知，我们在 vb.net 中有一种新语法，可以创建内联任务，因此我们可以异步运行它。

这是正确的代码：

        Dim testDeclaring As New Task(Sub()

                                      End Sub)
        testDeclaring.Start()

但现在我需要在子例程中传递一个参数，但我找不到正确的语法。有没有可能？

Answer 1

如果你想传递一个参数，你可以这样做

    Dim someAction As Action(Of Object) = Sub(s As Object)
                                              Debug.WriteLine(DirectCast(s, String))
                                          End Sub

    Dim testDeclaring As New Task(someAction, "tryme")
    testDeclaring.Start()

Answer 2

这是不可能的。但是，您可以只使用当前范围内的参数：

Public Function SomeFunction()

    Dim somevariable as Integer = 5

    Dim testDeclaring As New Task(Sub()
                                   Dim sum as integer = somevariable + 1  ' No problems here, sum will be 6
                              End Sub)
    testDeclaring.Start()

End Function   

Answer 3

不知道你是否在寻找这个：

Dim t As Task = New Task(Sub() RemoveBreakPages(doc))

Sub RemoveBreakPages(ByRef doc As Document)
        Dim paragraphs As NodeCollection = doc.GetChildNodes(NodeType.Paragraph, True)
        Dim runs As NodeCollection = doc.GetChildNodes(NodeType.Run, True)
        For Each p In paragraphs
            If CType(p, Paragraph).ParagraphFormat().PageBreakBefore() Then
                CType(p, Paragraph).ParagraphFormat().PageBreakBefore = False
            End If
        Next
    End Sub

问候。